A. Field of the Invention
The present invention relates generally to a so-called particulate trap, which catches particulates, contained in exhaust gas from a diesel engine or the like, by means of a filter, and burns the caught particulates to recover the initial flow resistance of the filter, and more specifically to an exhaust-gas purifying apparatus of the particulate trap-type.
B. Description of the Prior Art
Stated in Japanese Patent Disclosure No. 60-127685 is a support structure for heat generating members, formed of heat-resistant material.
The prior art invention relates to a heater for heating a vacuum degassing furnace, using fragile carbon electrodes. Each carbon electrode is a hollow, cylindrical electrode, one end of which is supported on a support structure, by means of a coupling member fitted in the electrode. The other end of the electrode is supported mechanically on a copper pipe, inserted therein, by means of a clamping cap. Thus, the electrode is supported like a cantilever, as a whole. Both ends of the carbon electrode are connected to a current source, by means of the coupling member and the copper pipe, individually.
This arrangement, in which the carbon electrodes are cantilevered, is advantageous in that the electrodes require no center-alignment, and can enjoy a prolonged working life.
The aforesaid conventional support structure cannot, however, support conductive-ceramic heater elements in a particulate trap. Since conductive ceramic is a highly brittle material, the cantilever structure tends to cause breakage of the heater elements. If the heater elements are hollow, moreover, they can be easily broken by stress, due to thermal expansion caused by heating.